Manufacturing insulating glass units (IGUs) typically involves applying a heat activated sealant material to a spacer frame, sandwiching the spacer frame and sealant between glass lites, and passing the assemblage through an oven and a roller press. The sealant is heated in the oven and the roller press forces the lites and heated sealant together so the IGU has a predetermined thickness and the glass and sealant are hermetically joined.
Typical ovens run at about 800 F.degree.. The IGUs are conveyed slowly through the oven so that the sealant material is heated sufficiently to flow and form a hermetic bond with the glass lites. At the same time the remaining IGU components are heated significantly above room temperature.
In the past, IGUs delivered from the roller press were stacked and allowed to cool for a substantial period of time--often hours. After cooling, an open vent port, which extended through the spacer frame between the ambient air and the IGU interior, was closed and sealed in a separate operation. Typically, a rivet was installed in the port, after which a sealant material was applied to the IGU edge to seal any leakage paths around the rivet.
When so called "low emissivity" IGUs were produced, the cooled IGUs were filled with Argon, or other suitable inert gas, before the vent port was closed and sealed.
Cooling IGUs is a necessary step in their manufacture. If the vent port is closed and sealed before the IGU has cooled, the air or gas sealed in the dead air space cools along with the IGU. As the entrapped air or gas cools, its pressure is reduced below atmospheric pressure. Consequently, the glass lites are bowed inwardly towards each other by the atmospheric pressure exerted on them. The result is an unacceptable IGU.
The necessity of cooling the IGUs resulted in a serious manufacturing bottleneck. Production machinery was capable of fabricating significant numbers of partially completed IGUs in a short period of time. But the IGUs then had to be stacked and permitted to sit idle for substantial periods of time as they cooled to ambient temperature. Furthermore, the subsequent steps of closing and sealing the vent ports--and introducing inert gas when required--were essentially manual operations that have been difficult and time consuming to complete.
The present invention provides a new and improved method of manufacturing IGUs wherein individual IGUs emerging from an oven and press are rapidly cooled and hermetically sealed while being conveyed to a location where the completed IGUs may be assembled into a window or other frame or prepared for shipment to a remote assembly location.